Anisotropic decay of polarized fluorescence of FAD in water-methanol solutions

Fluorescence kinetics of the biological cofactor flavin adenine dinucleotide (FAD) in water-methanol solutions at 0%, 20%, 40%, 60% and 80% methanol concentration have been investigated. Fluorescence lifetimes, corresponding weighting coefficients, anisotropy, and rotational diffusion time were determined from experiment through analysis of the polarized fluorescence decay excited by picosecond laser pulses. The dependence of the fluorescence parameters on solution polarity and viscosity has been analyzed.